The alginate fiber is a biodegradable fiber prepared through wet spinning using sodium alginate as the raw material. The alginate fiber is widely applied due to its excellent biodegradability and biocompatibility, great water absorbency and film-forming and fiber-forming capability, and has great potential in applications to high-grade clothing, underwear fabrics and decorative fabrics.
When the alginate fiber currently researched at home and abroad is contacted with a solution containing Na+, K+ and H+ ions, an ion-exchange interaction occurs between these ions and divalent cations contained in the alginate fiber, such that the fiber is swelled to break coordination-crosslinking structures within the alginate fiber, leading to a loss of fiber morphology, and even completely dissolution of the fiber. This defect results in that when the alginate fiber is applied in the textile field, not only is a failure of dyeing and finishing processes of the fiber caused, but also the fabric cannot be washed with a common detergent, which greatly limits the application of the alginate fiber in the textile fabric field.
Although currently there are some reports for researches on salt-resistant alginate fibers in the prior art, some shortages still exist. For example, Chinese patent CN 101956320 A discloses a method for reducing the swelling degree of a calcium alginate fiber, wherein a calcium alginate fiber processed by such a method has a reduced swelling degree in a NaCl solution; there are also some researches on modification of a calcium alginate fiber by aluminum sulfate, and for example Zhang Chuan-jie et al. Modification of calcium alginate fibers with aluminum sulfate solution (Journal of Functional Materials, 2012-7, Vol 43(13), 1752-1755) and Wang Heng-zhou et al. Structure and properties of aluminum sulfate modified calcium alginate fibers (Textile Auxiliaries, 2013-3, Vol 30(3), 5-11) reported methods for improving the salt resistance of calcium alginate fibers through modification by aluminum sulfate, and the calcium alginate fibers processed by such methods has a significantly improved resistance to normal saline, but the alginate fibers processed by the aforementioned methods will be dissolved rapidly when coming into contact with a alkaline detergent, such that a fabric made of such an alginate fiber cannot meet the requirement for daily use; Zhang Min et al. from Tianjin University prepared a degradable alginate hydrogel microcarrier for in vitro culture of mesenchymal stem cells by crosslinking oxidized sodium alginate-gelatin with sodium tetraborate (master's thesis of Tianjin University, 2006-1), wherein such a carrier has excellent resistances to salts and alkalis, but the raw material, the finished product and the preparation process of this method are all significantly different from the existing manufacturing processes of alginate fibers, and thus cannot be applied in manufacture of alginate fibers; Chinese patent CN 101718010 B provides a method for preparing an alginate fiber, in which an alginate fiber is prepared directly from alga as a raw material using epichlorohydrin, borax, toluene diisocyanate or a dialdehyde compound as a crosslinking agent, but since the main object of this method is to prepare a fiber product with mechanical properties similar to the existing alginate fiber directly by using alga as the raw material, the effects of impurities contained in the raw material alga on the salt resistance and the detergent resistance of the alginate fiber had been ignored, such that the salt resistance and the detergent resistance, and particularly the detergent resistance, of the alginate fiber cannot meet the application requirements of textile fabrics.
Therefore, it is an urgent technical problem to be solved in the textile field to provide an alginate fiber which is not only salt-resistant, but also detergent-resistant.